| This trial was carried out at the Yucheng Comprehensive Experimental Station, Chinese Academy of Sciences, located in Shandong Province, China. The experiment was originally designed with five different water application treatments. They were: the treatment no irrigation and rainfall; the treatment with 60% of maximum field moisture capacity (FC) as the bottom line of irrigation; the treatment with 80% of FC as the bottom line of irrigation; the treatment of drought in jointing stage and the treatment of drought in grouting stage respectively. Soil moisture condition, crop growth and development, photosynthesis, dry matter accumulation and partition, and other characters were observed through the entire period of the experiment. The process and mechanism of physiology for winter wheat under different soil water conditions were researched and analyzed by means of Crops culture, Agricultural meteorology, Plant physiology and ecology. Agricultural statistics, Applied mathematics and so on. Effects of different water conditions on dry matter accumulation and partition of winter wheat were compared. Based on the two purposes of promoting yields of crops and water use efficiency, the treatments thatwere of significant effects on yields and water use efficiency were selected for irrigation practice in water-saving agriculture in Yucheng area. The results indicated:1. The result of fuzzy comprehensive judgment showed the treatment with 60% of FC as the bottom line of irrigation was the optimum. Therefore, the bottom line for optimum soil water content is 60% of maximum field capacity in Yucheng area.2. The contributions of different crop apparatus to yield were different under different soil water conditions. The contribution from stem to yield was 0.308g/plant with the treatment of 60% of FC as the bottom line of irrigation, being highest in five treatments. Under the treatment with 80% of FC as the bottom line of irrigation the contribution to yield from stem was the lowest, only 0.030g/plant.3. The proportions of ground apparatus were different in different water application treatments. They were 10% of leaves, 10% of sheaths, 24% of stem, and 56% of spike in the treatment with 60% of FC as the bottom line of irrigation. The proportions of stem were higher under the treatment with 80% of FC as the bottom line of irrigation and in treatment of no irrigation. They were 36% and 37% under the two treatments respectively. And the proportions of spike under the above two treatments were lower. They were 43% and 48% respectively.4. The coefficient of yield to soil water condition was used to reveal the reducing of yield when evapotranspriation was shortage. The result showed grouting stage was one of water sensible stages in wheat growing period. Due to drought in this stage the yield reduced more, and the coefficient of yield to soil water condition was 1.77, being the highest in treatments. The coefficient of yield to soil water condition of drought in jointing stage was 0.94. The coefficient with the water the treatment with 60% of FC as the bottom line of irrigation was 0.13, denoting the soil water condition was suited for high yield of winter wheat. The coefficient under the water treatment with 80% of FC as the bottom line of irrigation was -0.88 and showed that the soil water content was overabundant to winter wheat. The coefficient under the treatment of no irrigation in the whole growing stage was 0.99.5. Amount of water supplied by groundwater to wheat throughout jointing to maturity stages in the groundwater-enriched area was 65mm. This amount was about 22% of total water consumption of winter wheat in the same period.6.The evapotranspiration to highest yield was 473mm. This number was derived from dry matter yield and the yield simulated out of maximum evapotranspiration, and the highest theory yield was 6240 kg/ha. The evapotranspiration was 403mm when water use efficiency was highest.7.During middling rainfall years, the irrigation was 190mm in entire growing period of wint...
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